Surfaces cache token data in the analytics views and fixes table
spacing.
### Changes
- **Cache token columns**: Added cache read and cache write token counts
to all analytics views (user and admin), from SQL queries through Go SDK
types to the frontend tables and summary cards.
- **Table spacing fix**: Replaced the bare React fragment in
`ChatCostSummaryView` with a `space-y-6` container so the model and chat
breakdown tables no longer overlap.
### Data flow
`chat_messages` table already stores `cache_read_tokens` and
`cache_creation_tokens` (and uses them for cost calculation). This PR
aggregates and displays them alongside input/output tokens in:
- Summary cards (6 cards: Total Cost, Input, Output, Cache Read, Cache
Write, Messages)
- Per-model breakdown table
- Per-chat breakdown table
- Admin per-user table
Michael Suchacz
969066b55e